This invention relates to plow and scraper assemblies and more particularly to plow and scraper assemblies having blades detachably removable from the mould board.
Generally, when plow and scraper assemblies are used for the removal of snow or ice or for the leveling of road surfaces, the scraper blades are easily damaged or worn down, necessitating repair or replacement. Since it is cumbersome and unrealistic to remove an entire plow or scraper assembly from the vehicle each time the blade must be removed, the plow and scraper assemblies incorporate detachable blades.
These prior art detachable blades are almost universally secured to the plow body or mould board of the plow assembly with a plurality of bolts. However, the use of fastening bolts has been found to be expensive as well as dangerous. The most severe problems exist with plow assemblies used for snow and ice removal, since the bolts become rusted, corroded, and difficult to remove.
Generally, it is necessary to cut, break, or burn the bolts off in order to remove the blade. This necessitates spending a great deal of manual effort. Furthermore, the incidence of injury during the removal of the blades was quite high, since force is typically required to dislodge the bolts, resulting in the shattering and aerial propelling of portions of the bolts.
Although various prior art systems have been developed in an attempt to eliminate the difficulties inherent in the use of bolts, no system has been developed which matches the ease of operation and secure, repeatable locking attachment of the present invention.
The following is a list of prior art references which are believed to be pertinent:
______________________________________ U.S. Pat. No. Issue Date Inventor ______________________________________ 3,477,520 11/11/69 J. J. Gray 3,202,226 8/24/65 C. W. Carson 3,190,018 6/22/65 M. P. Nelson 3,090,140 5/21/63 V. E. Trana 1,741,933 12/31/29 J. H. Gunnison 1,885,231 11/1/32 L. L. Chong et al ______________________________________
Gray, U.S. Pat. No. 3,477,520, employs a plurality of horizontal slots in the plow body, coupled with wedge blocks mounted to the plow blade which interfit with the slots in the plow body. This greatly increases the cost of the manufacture of the plow blade and the plow body. Carson, U.S. Pat. No. 3,202,226, uses a complicated system of interlocking trapezoidally shaped wedges mounted on the plow blade which fit into similarly shaped sockets in the plow body. Further reinforcement and securing members are necessary in order to hold the plow blade securely in position. Nelson, et. al, U.S. Pat. No. 3,190,018, also teaches the use of lugs mounted on the plow blade that fit through slots in the plow body. Apertures in the lugs are designed to receive a tapered bar which acts to pull the blade in tight abutment with the plow body. This invention also involves much expense in manufacture.
Trana, U.S. Pat. No. 3,090,140, utilizes an aperture cut into the plow body to receive the plow blade. The blade is held in place by frictional means. Gunnison, U.S. Pat. No. 1,741,933, also uses projections mounted on the plow blade to interfit with flanges on the plow body. Cotter keys are used as attachment means in the Gunnison invention. Finally, Chong, U.S. Pat. No. 1,885,231, teaches the use of a slotted screw attachment system for mounting a small blade onto a garden tool structure.
Although these various prior art attempts have been made to provide an inexpensive and reliable blade securement system, these prior art systems have failed, and only produced a variety of expensive, cumbersome constructions which do not overcome the continuing problems of ease of installation and removal, low manufacturing costs, simplicity of operation, and secured engaged attachment of the plow blade to the plow body.
Therefore, it is a principal object of this invention to provide a plow and scraper assembly in which the plow blade is quickly and easily installable and removeable from the plow body or mould board.
Another object of this invention is to provide the plow and scraper assembly having the characteristic features defined above wherein the plow blade remains in secured engagement with the mould board throughout its use when mounted therewith.
Another object of this invention is to provide the plow and scraper assembly having the characteristic features defined above wherein both the plow blade and plow assembly are inexpensively manufactured and capable of operative use with a minimum of effort.
Other and more specific objects will in part be obvious and will in part appear hereinafter.